Manufacture of aromatic acids



Patented July 12, 1932 UNITED STATES PATEN GFHCE v HUGH ALBERT EDWARD DRESCHEB, DAVID AnnxAlvDnngwnmrAiawn rnan;Ann JOHN THOMAS, or GRANGEMOUTI-I, soorL un; .A'ssrenons' mo SCOTTISHMDYES, LIMITED, OFLGRANGEMOUTH, SCOTLAND Q A v MANUFACTURE or 4 mm ACIDS I in Drawing. Application filed. July 6, 192a, Serial Ne, 376,487, and in-anaemia. u'- ust 4 ,-192s.'

This invention relates to the production of Vat dyestuif intermediates and the like, particularly to the production of oi-naphthoic acid or benzoic acidor both bodies, and also to the action of alkaline earth metal salts of a-naphthoyl-ortho-benzoic acid underheat in the presence of an oxide or hydroxide of an alkaline earth metal.

The object of the invention is to provide improved or modified process for the producketone we can obtain a mixture of a-naphthoic acid and benzoic acid.

Gabriel and Coleman Berichte, 1900, 33, 448, have described the obtaining of a-naphthoic acid from. a-naphthoyl-ortho-benzoic acid by fusing with caustic potash, but they obtained considerable quantities of naphthalene, and stated that the yield of a-naphthoic acid was only small.

In comparison with that process, the proc- V ess of the present application has the economic advantage that the caustic potash may be replaced by a much cheaper compound, viz., calcium hydroxide.

The invention in brief consists in the process which comprises the subjection of alkaline earth metal salts of a-naphthoyl ortho-benzoic acid to the action of heat in, the presence of a hydroxide of an alkaline earth metal for a short time for the production of a-naphthoicacid and benzoic acid.

The invention also consists in the application of the process of the preceding paragraph to yl ketoneecarboxyl c-acidsgena erally; A p

Theinv'ention-alsoconsists inwprocessesrsub I I stantially as herein described,-and in products whichunay be made thereby...

The :following. examples; illustrate how: the invention. may be carried; (intoetfect; all. parts being-parts byweighter tiwomtple 1 t The sodium salt'jof Q-aQnaphthOyI benZoic acid is dissolved in.. -wate r andg calcium chloride. added; Theepreci-pitate of the. cal- A cium salt 1 which :forms; is. filtered ofl? Yand .1 v

dried. I 50. partsgof thiscalcium saltare mixed' with 13.6 parts, ofcalcium hydroxide o-ffl92% j strength, and heated The mass -becomessliq-t uidai-and homogeneous. Itisstirredandithe temperature raised to1- aboutBQO:$01350? C. i

It is keptat this for about 15 minutes V A The heating visthen stopped- :and the mass cooled. and brokenflup- It. is? boiled with a.

solution. offsodium.carbonate-and the cal-K H cium carbonate which isprecipitated filtered offv and washed.

The combined"'filtrates and diluted to about11200 fparts, .raisedfto' the precipitated by i5 boil {and "the. IIB Phthoic Eacid the-addition of hydrochldricfacid. j Y

. =-The- :naphthoic acid is filteredofli hot and washed with hot water: Theprod-uct' without further: :purifica-tion: is? iwhitew in ,lcoleurrrand melts. art- 9! to 1160 Ci! Thafiltrata-isnllowed tocoel-whenjthei benzoicacidcrystallizes out and is filtered ofi'p.

-EaamPle-2- a p parts of, 92% calcium hydroxide are. Wellmixed l 'togetherin ;the ffo rmiof a. paste ;witli water Themixture isthen'fdried;itffi'rstebe With S KS parts'of*92%calcium hydroxide'and A comesliiliiidiand,then sets soli d"again,if"' QO'paI'ts Oft-he'driedproiluct'are then mixed 9U heated. The mixture first liquefies and then to becomes stifi again.

The temperature is raised to about 300- names to this specification.

350 C. for a few minutes. The mass is allowed to cool, broken up and dissolved in 200 parts of water with sodium carbonate, the lime removed by filtering, the filtrate acidified and left to crystallize. The resulting crystals of benzoic acid are then filtered ofi.

General The invention is not limited to the above examples, but includes for instance di-arylketone-carboxylic acids generally. In some cases such as Q-benzoyl-benzoic acid a single product is obtained, e. g., benzoic acid, but usually two difierent carboxylic acids are obtained. Thesemay be separated by making use of thedifi'erences in solubility of the two acids or their salts'in water or in other solvents or by sublimation. Substituted ketone-carboxylic acids may be employed in the reaction for the production of substituted carboxylic acids. V

By working according to the examples given above, the reaction proceeds very smoothly, and yields approaching the theoretical are obtained while the products are of excellent quality.

If desired, the starting materials maybe prepared from the cheap and readily availablephthalic anhydride. i Having now described our invention, what we claim as'new and desire to secure by Letters Patent is I 1. The process whichconsists'in' heating together the calcium salt of 2-anaphthoyl benzoic acid and calcium hydroxide for a shorter time than is necessary to produce phenyl naphthyl ketone and until the mass becomes liquid, raising the temperature to about 300 to 35.0 0., cooling the mass, treating it with a solution of an alkaline carbonate separating the calcium carbonate thus formed, diluting the'liquor, raising it to the boil and adding hydrochloric. acid for the precipitation of the naphthoic acid.

. 2. A process for the production of u-naphthoic acid and benzoic acid which consists in heating alkaline earth metal salts of a-naph- V thoyl-ortho-benzoic acid in; the presence of an hydroxide of an alkaline earth until sam ples show that substantially none of the starting material remains and substantially 'no phenyl-naphthyl ketone is formed. 3. A process for the production of a-naphthoic acid and benzoic acid which consists in subjecting alkaline earth 'metal salts of oznaphthoyl-ortho-benzoici acid to the action of kaline earth metal for a shortertime than is heat in the presence of an'hydroxide of analnecess'a'ryto produce phenyl-naphthyl ketone. 4. A process as claimed inclaim 3 applied HUGH ALBERT EDWARD DRESCHER. DAVID ALEXANDER WHYTE FAIRWEATHER.

JOHN THOMAS. 

